The following relates generally to wireless communication, and more specifically to enhanced multicast broadcast multimedia service (eMBMS) in enhanced component carriers (eCC) over a variable transmission bandwidth.
Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, and orthogonal frequency division multiple access (OFDMA) systems. A wireless multiple-access communications system may include a number of base stations, each simultaneously supporting communication for multiple communication devices, which may be otherwise known as user equipment (UE).
Base stations may use Single Frequency Network (SFN) technology to distribute broadcast streams into defined areas during the same radio time slot. SFN transmission in a Multimedia Broadcast Multicast Service (MBMS) or eMBMS may achieve high broadcast capacity with multiple base stations synchronously transmitting the same contents. SFN transmissions from different cells may use the same set of communication resources (e.g., a same set of one or more radio frequency spectrum bands) and modulation and coding scheme (MCS) such that they appear to receiving UEs as coming from a single base station.
MBMS may also be used in a shared radio frequency spectrum band (e.g., an unlicensed radio frequency spectrum band). Multicast/Broadcast over a Single Frequency Network (MBSFN) on a shared radio frequency spectrum band may involve Listen-Before-Talk (LBT) procedures based on a clear channel assessment (CCA) or an enhanced CCA (eCCA). Thus, not all base stations may gain access to the communications medium, or the same portions thereof, during every time period. The condition where base stations gain access to different portions of a communications medium may interfere with synchronous transmission of the same content on the same resources from each base stations, which may result in a degraded signal at receiving UEs and/or degraded delivery of service to receiving UEs.